Densification behavior and mechanical properties of spark plasma reaction sintered ZrB2–ZrC-B4C ceramics from B4C-Zr system

Abstract The ZrB 2 -ZrC-B 4 C multiphase ceramics were produced by spark plasma reaction sintering (SPRS) from boron carbide (B 4 C) with different volume of zirconium (Zr). With Zr content increases, the B 4 C phases in the composite decreased gradually, and the zirconium carbide (ZrC) phase gradually increased. With Zr content increased to 70 vol%, the morphology of the zirconium diboride (ZrB 2 ) changed from equiaxed crystal to platelet crystal. During the solid reaction process of Zr with B 4 C, carbon (C) was preferentially replaced to generate ZrB 2 , and then the remaining Zr reacted with C to form ZrC. With the increase of Zr content, the flexure strength and fracture toughness of the ZrB 2 -ZrC-B 4 C composite ceramics increased due to improved microstructure and more crack deflection and intergranular fracture.